Drosophila Research Paper

The research done in the paper involved the study of Drosophila’s immune system. The authors focused on the orthologs and paralogs of immune system genes from the twelve genomes of Drosophila. The big picture is to understand how genetic factors influence the fluctuation in the defense against infection. The experimenters used viruses and other pathogens to prove that genetic variations in the immune system using Drosophila and genetic mapping to identify the genes involved. The Drosophila have to evolve in order to survive. Therefore, they use natural selection to survive against the thriving viruses. Evolution increased the binding ability of certain receptors to the pathogen indwelling immune response. This paper is an original, written by the researchers. The main hypothesis of the paper is to show that species evolve through adaptive evolution of immune responses against competing evolving pathogens.

In order to study the variation among immune system genes, the experimenters used codon substitution models of molecular evolution. This model requires nucleotide alignments and are less reliable at high synonymous divergence which then limited the experimenters to six species in the melanogaster group. This model tested three different kinds of immune-genes: recognition, signaling, and effector. They used this method to find that the proportion of positively selected genes was highest in the recognition genes which is most important in reorganizing and binding pathogens. They tested positive selection by comparing the probability of data under a model that requires a subset of codons to have certain patterns. Null model had some genes rejected; these genes had significantly more nonsynonymous substitutions than the expe...

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...estimate the patterns observed in species that have both adaptive and innate immune systems. Also, this information can be used to perform an experiment on a different organism to relate the innate immune pathways.

This paper fit into my groups’ concept map under environmental adaptations. Environmental adaptations are an inherited trait that make organisms survive better in their environment; although the genes adapted to compete with pathogens, they were also inherited. Adaptation is a key component to natural selection, the topic of our concept map. Therefore, natural selection affects gene families and some genes in the innate immune system, like recognition and signaling, into evolving in order to survive. Certain genes interact with their environment for survival which proves how natural selection is linked to the experimenters’ hypothesis and conclusion.